Method of protecting articles from earth-currents.



H. GEPPERT.

METHOD OF PROTEGTING ARTICLES FROM EARTH GURRENTS.

APPLICATION FILED r3124, 1909.

Patented Apr. 18, 1911.

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provements in the Method for Protecting.

Articlesfrom Earth-Currents, of which the following is a s ecification.

Metallic artic es, such as gas and water pipes, telephone and telegraph cables, bridge anchors and posts, embedded inthe ground, are exposed to destruction by the chemical action of the soil and by-the electrolytic action of earth currents (roving or stray our- I railway track; b is a pipe and 0 (Figs. 2 and rents) which are mainly generated by the working current lighting plants. Means. are already known by which earth currents of this kind can. be rendered more or less harmles's by special protective circuits. According to the present invention also, a protective circult is provided for the same purpose, the same differi'ng, however, in many respects from the known methods both in its mode of application and action. The article to be protected is connected with the negative pole of anyconvenient source of electricit (cells, accumulators, dynamos), while at t e same time, anodes sunk into the earth in suitable positions, are connected with the positive pole of the same source of electricity.

Figure 1 of the drawing gives a diagrammatic view of the device according to this invention; Fig. 1 is a similar view of a modification; Fig. 2 is a plan of Fig. 1 and Figs. 3 and 4 are cross sections.

a represents the rail of the tramway or 3) a cable that is exposed to destruction by earth currents, and for which protection against the latter is desired. (1 represents the anodes that are sunk in the ground for this purpose, and e the electricalconductor 45- conveying the current to. the anodes d, the conductor being connected up with the positive pole of any convenient-source of electricity f (Fig. 1). The negativev pole of th source of current f is electricall connected with the. ipe b, to be protecte by means of a con uctor Hence a current flows from the source f in the direction of the arrows 12. from the electrodes at and through the ground to the pi b.

It is known that t e current escaping into i Specification of Letters Patent. Application filed rebruery 24, 19.08. Serial No. 479,788.

the earth sets up 1 entering current of electrical tramway andthe wire resistance 8 in Fig. 1) and by Patented Apr. 18, 19.1.1.

an electrolytic action on ch it escapes; whereas the protects the body in which it enters, 'in consequence of the generation of hydrogen. Hence a protective circuit f-e dlb-bgf is formed, which, though exposing the anodes d to destruction, protects the pipe b.

he working current of the tramway the body from w passes from the source of current i throu h the overhead wire 1:, the earl (Fig. 1 dotted lines) the rails a and the conductor m (Fig. 1) back to z. A portion of the working current passes from the car Z through the rails a, in the direction of the arrow n (Fi 1) through the earth to the pipe I). I the source of current f be now switched off, this part of the working current makes it escape (at those parts of the tram or railway installation where the tension in the rails a is correspondingly lower) from the pi e 1) into the earth flowing in the direction 0 the arrows 0', and toward the rails a. In conseuence' of this, the pipe I) is subjected to e ectrolytic corrosion. If, however, the source of current f be switched on, then, as stated above, a current flows from the anodes cl in the direction of the arrows it throu h the earth to the pipe I), and, given a suiiicientl high tenslon of the auxiliary current urnished by f, the workingcurrent 'is prevented from issuing from the pipe I), in the direction marked .by the arrows o. The working current flows through the conductorg, the source of current f and the conductor e to the electrodes d, and in the direction of the arrows p through the earth to the rails a and through the conductor m back to the source 2' of the working current. The device according to this invention presents, the advantages that the rails are not corroded at n or r, and that the earth currents generated by the auxiliary circuit are relatively small, owing to the presence of an earth resistance between the anodes al and the rails ar, while direct connection between the pipe I) '(or cable 0) and the rails, the working dynamo or the overhead wire is prevented. v

Under certain conditions the earth ourrents can be still further lessened by the interposition of suitable resistances (c. g. mak-- ing the anodes dsmall or of material of *low conductivity.

'2 and 3).

The arrangement as described is usually provided only in the vicinity of the genera'ting station 2'. However, it may be extended so as to embrace a greater or less amount of trackage as well; the destructive earth currents will then be reduced substantially in proportion to the extent of trackage thus included.

The particulars given in respect of the pipe 5 apply equally to lead cables 0 (Figs. The rails a also may be specially protected in the same way at suitable parts of the track, by a source of current if (Fig. l; dotted lines) and anodes u.

The anodes (Z and u are embedded in the earth in any way that circumstances may render desirable; or they may also be on the surface of the ground provided they are, in suchcase, placed in adequate electrical contact with the earth.-

The strength of current passing between the anodes d, the pipe Z) and the cable 0 will naturally be cut down to the smallest practicable figure in order to save expense, and therefore the anodes should be distributed in the manner best adapted to the needs of each case, and should also be as small as possible, in order to increase their electrical resistance and to allow only a weak current to pass even when the voltage is high.

in order to insure adequate electrical contact between the anodes d and earth, even in dry weather, the anodes (I may be surrounded with damp clay, earth saturated with brine, or some equivalent mass. They are preferably made interchangeable or of inert or non-corrosive material (6. g. carbon, nickel, platinum, gold) or coated with same, and may be of any convenient shape.

If the conductor e be in the ground and not insulated it may serve direct as the anode; and in the event of insulated conductors 6 being sheathed in metal, the sheathing may also be connected up with the negative of the auxiliary source of electricity and thereby protected from destruction.

If the articles to be protected are situated in running water for instance then the anodes will also be submerged in the water.

The device in accordance with this invention maybe put to a variety of uses. Thus, for instance, Fig. 4 indicates how it can be used to protect an iron standard from corrosion. Here the anodes are also marked (Z and the corresponding conductors e; and the method of operation is the same as described above.

Now what I claim and desire to secure by Letters Patent is the following:

1. The improvement in the art of preventing electrolytic decomposition of underground pipes by reason of stray currents from electrically operated railway systems, which consists in negatively electrifying said pipes and establishing a line of positive electrification closely adjacent to said pipes, substantially as described...

2. The improvement in the art of preventing electrolytic decomposition of underground pipes by reason of stray currents from electrically operate railway systems, which consists in nega -ely electrifying said pipes and establishing a line or" positive electrification adjacent to and at a substantially uniform distance from said pipes, substantiaily as described.

3. The improvement the art of preventing electric decomposition of underground pipes by reason of stray currents from electrically operated railway systems, which consists in connecting the negative pole of an independent circuit to the pipes and the positive pole of said circuit to conductors arranged adjacent to said pipes and then supplying electricity from said independent circuit substantially as described.

4. The improvement in the art of preventing electric decomposition of underground .pipes by reason of stray currents from electrically operated railway systems, which consists in creating a region of positive electrification adjacent to said pipes, and then negatively electrifying both said pipes and the rails of the system, thus causing current to flow from said region to both said pipes and to the rails of the system, substantially as and for the purpose described.

5. In combination with the rails of an electrically operated railroad system, said rails being used to carry operating current, a source, of electricity, underground pipes, and conductors arranged adjacent to said pipes, said pipes and conductors being respectively joined to the negative and positive sides of said source of electricity, substantially as described.

In testimony, that I claim the foregoing as .my invention, I have signed my name in presence of two witnesses, this eleventh day of February, 1909.

I I-ERMANN GEPPERT.

VVitn'esses:

Jos. H. LEUTE,

N. ROMARED. 

